Fuel Starvation or bad fuel pump?

[yaoxiao4]

Hello,

I used to get fuel starvation when I'm below 70% dots on right turn sweepers, so I used to fill up after EVERY session and that's been fine. But yesterday I filled up before a 25min session and fuel starved 9-10 laps in (2 mile course), I was wondering if this is just because I'm driving harder now OR my fuel pump is going bad?


as for solving the issue, I'm looking at CJM and Z1 solution, Z1 is much cheaper but I'm not sure the advantages or disadvantages are (I read the fuel starve thread but am still a bit confused what the disadvantage for Z1 to have both pumps running at all times). Car is 80% track 20% mountain roads.

[AlWakRa]

Most likely broken fuel pump hat, I had the same issue and my car starved after I lose only one dot. CJM fuel pump hat is the way to go, and install anti-fuel starvation kit at the same time.

Personally, I have CJM road race fuel pump, a friend bought Z1 kit, but sold his car before getting the chance to install it.

[yaoxiao4]

Originally Posted by AlWakRa

Most likely broken fuel pump hat, I had the same issue and my car starved after I lose only one dot. CJM fuel pump hat is the way to go, and install anti-fuel starvation kit at the same time.

Personally, I have CJM road race fuel pump, a friend bought Z1 kit, but sold his car before getting the chance to install it.

Yeah I was looking at that, but its almost double in price and if they do the same thing then I'm curious as to what the differences are.

do you have any issues with the CJM one? both on and off the track

[AlWakRa]

When I bought my CJM, there wasn't a lot of long term reviews for Z1 kit, which turned to be a very good option and some track guys like Hotrodz running it.

Also, I don't have any issue with RRP, I think installation will be more time consuming than Z1 kit + increased fuel pump noise, but very satisfied that I don't get starvation any more. I dealt with both, CJM and Z1, and I had great experience with both.

[yaoxiao4]

yeah, I see a lot of guys running Z1 but mostly on track only cars, I wonder what kind of disadvantages it has on the street.

[cv129]

Originally Posted by yaoxiao4

yeah, I see a lot of guys running Z1 but mostly on track only cars, I wonder what kind of disadvantages it has on the street.

Phunk's post

Holley's Hydramat is now shipping - fuel starve solution?

In short, potentially shortening lifespan of the fuel pump (that comes with the Z1 kit) due to pumping on an empty tank on the driver's side.

For longevity during street use, the solution would be keep it above 1/2 tank at all time, or add a switch to turn the pump off.

[yaoxiao4]

ah sounds good, but CJM has no issues like that?

[cv129]

Originally Posted by yaoxiao4

ah sounds good, but CJM has no issues like that?

"The CJM RRP is a surge can system that operates under an entirely different principle and it is normal and required that both pumps run all the time."

[yaoxiao4]

Originally Posted by cv129

"The CJM RRP is a surge can system that operates under an entirely different principle and it is normal and required that both pumps run all the time."

haha yeah I read that, was just confused on what it means, but I'm assuming it just means there no really downside like the Z1 has

will probably shell out money on the CJM one then

[2011 Nismo#91]

Assume about 6mpg on the track. So after 9-10 laps at 2 miles each that's 3.4 gallons. It could happen especially if the tank wasn't quite full at the start. The CJM RR setup though you can't go wrong with, had it for years now with no issues. Even ran the car on the track once to the point where the fuel gauge showed no fuel, there was still about 3 or 4 gallons in there based on how much I filled up with, and there was no fuel starve. I think the fuel hat breaking issues is hit or miss, happens to some with just street driving doesn't happen to others even on the track. But if your going in there already it can't hurt to do it. It wasn't available when I installed my RR pump otherwise I would have probably done it.

[SS_Firehawk]

Like others have said it is a failing tophat. Mine was on it's last leg and severely leaning to one side. That CJM tophat is a seriously nice piece and won't break. The CJM RRP solution is in line, so the stock pump fills the canister and the RRP pump pushes it back to the passenger fuel assembly. Both pumps are constantly running still. I just finished installing the CJM tophat and RRP with upgraded 450 pumps and full return system. I have to go back in to band one of the baffles further as the driver side float is still acting up.

[Rusty]

I have the RRP from phunk. One of the first ones made. It's been great. I don't have to worry about turning the pump on and off. Just start the car and go. I've ran the tank down to one dot and it was still working on the track.

[ban25]

The faster you get, the higher your lateral Gs -- especially if you upgrade your tire compound -- the sooner you will fuel starve. I would get fuel starve after only 2-3 hot laps at BW and ACS, starting from a full tank.

[yaoxiao4]

Originally Posted by ban25

The faster you get, the higher your lateral Gs -- especially if you upgrade your tire compound -- the sooner you will fuel starve. I would get fuel starve after only 2-3 hot laps at BW and ACS, starting from a full tank.

aw man, I wanted to go to button willow within the next couple weeks too :/

[DarkJak]

I went with the Z1 solution due to budget, and it works. But the CJM kit is worth the extra. The Z1 kit is very easy to interfere with the tank level floats and overall kit quality isn't as nice as CJM's products.
Like others have mentioned it has the downside of just pumping fuel from the left half of the tank to the right bucket, nothing more.